Aortic valve replacement in pediatric patients: 30 years single center experience.

BACKGROUND: The choice of aortic valve replacement needs to be decided in an interdisciplinary approach and together with the patients and their families regarding the need for re-operation and risks accompanying anticoagulation. We report long-term outcomes after different AVR options. METHODS: A chart review of patients aged < 18 years at time of surgery, who had undergone AVR from May 1985 until April 2020 was conducted. Contraindications for Ross procedure, which is performed since 1991 at the center were reviewed in the observed non-Ross AVR cohort. The study endpoints were compared between the mechanical AVR and the biological AVR cohort. RESULTS: From May 1985 to April 2020 fifty-five patients received sixty AVRs: 33 mechanical AVRs and 27 biological AVRs. In over half of the fifty-three AVRs performed after 1991 (58.5%; 31/53) a contraindication for Ross procedure was present. Early mortality was 5% (3/60). All early deaths occurred in patients aged < 1 year at time of surgery. Two late deaths occurred and survival was 94.5% ± 3.1% at 10 years and 86.4% ± 6.2% at 30 years. Freedom from aortic valve re-operation was higher (p < 0.001) in the mechanical AVR than in the biological AVR cohort with 95.2% ± 4.6% and 33.6% ± 13.4% freedom from re-operation at 10 years respectively. CONCLUSIONS: Re-operation was less frequent in the mechanical AVR cohort than in the biological AVR cohort. For mechanical AVR, the risk for thromboembolic and bleeding events was considerable with a composite linearized event rate per valve-year of 3.2%.

Long-term outcomes after the paediatric Ross and Ross-Konno procedures.

OBJECTIVES: The Ross procedure is an attractive option for the management of aortic valve disease in paediatric patients. We reviewed our experience with the paediatric Ross procedure to determine survival and freedom from reoperation in the third decade after surgery. METHODS: We reviewed the data of 124 paediatric patients [71% male, median age at time of surgery 11.1 years (interquartile range 6-14.8 years); 63.7% bicuspid aortic valve], who underwent the Ross procedure at 2 tertiary centres from April 1991 to April 2020. The Ross-Konno procedures were performed on 14 (11.3%) patients. Deaths were cross-checked with the national health insurance database, and survival status was available for 96.8% of the patients. The median follow-up time was 12.1 years (interquartile range 3-18 years). RESULTS: There were 3 early and 6 late deaths. All early deaths occurred in patients aged <1 year at the time of surgery. The 25-year survival was 90.3%. Actuarial freedom from reoperation (linearized rates in parentheses) was as follows: Autograft reoperation was 90.8% (0.48%/patient-year) and right ventricular outflow tract (RVOT) reoperation was 67% (2.07%/patient year) at 25 years. The univariable Cox-proportional hazard analysis revealed younger age at time of surgery (P < 0.001), smaller implanted valve size (P < 0.001) and the use of a xenograft rather than a homograft (P < 0.001) as predictors of RVOT reoperation. At multivariable Cox-proportional hazard analysis, only age was an independent risk factor for RVOT reoperation (P = 0.041). CONCLUSIONS: The Ross and the Ross-Konno procedures are associated with good outcomes in paediatric patients. Reoperation of the RVOT is frequent and associated with younger age.

Predictors of outcome of non-ischemic mitral valve surgery.

BACKGROUND: Data on the risk stratification of patients undergoing mitral valve (MV) surgery for non-ischemic mitral disease are sparse. The present study seeks to define them in a contemporary cohort. METHODS: 193 consecutive patients referred to non-ischemic MV surgery were prospectively studied. Baseline characteristics and the type of surgery were analyzed with regard to operative and late mortality as well as functional outcome. RESULTS: 129 patients underwent MV replacement and 64 MV repair. MV replacement patients presented with more symptoms (p = 0.010), higher EuroSCORE (6.1 versus 5.6; p=0.009), more frequently underwent additional valve surgery (7.8 versus 0%; p = 0.003) and were more frequently female (p=0.048). Operative mortality was 3.1%, two thirds of operative deaths had additional surgery of the tricuspid valve (p = 0.019). Patients were followed for 5.2 ± 2.7 years. 1-, 3-, 5- and 7-year survival rates were 93-, 91-, 82-, and 79% in MV replacement patients versus 100-, 98-, 96-, and 89% in patients with MV repair (p = 0.015). However, by multivariate logistic regression, overall mortality was determined by additional surgery of the tricuspid valve (p = 0.0103), multivessel coronary disease (p = 0.026), and age (p<0.0001), but not by the type of surgery (p=0.066). Furthermore, the type of surgery did not influence functional outcome (p = 0.515). CONCLUSIONS: Apart from age and coronary artery disease the need for additional tricuspid valve surgery significantly determines the outcome of non-ischemic MV surgery. The type of operation appears less important when the need for additional valve surgery and co-morbidities like coronary artery disease are taken into consideration.

Midterm results of aortic valve replacement with cryopreserved homografts.

OBJECTIVE: The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts. MATERIALS AND METHODS: Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%), truncus arteriosus in 6 patients (15%), and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35%) patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients. RESULTS: The 30-day postoperative mortality rate was 12.5% (5 patients). There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003). The last follow up showed that the 27 (82%) patients had a normal left ventricular function. CONCLUSION: Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

Gender differences in clinical presentation and surgical outcome of aortic stenosis.

BACKGROUND: Little is known about the gender differences of patients undergoing aortic valve replacement (AVR) for isolated severe aortic stenosis. METHODS AND RESULTS: 408 consecutive patients (215 women and 193 men; p=0.9) were analysed. At presentation, women were older (73.7+/-9.3 years vs men 66.5+/-11.5 years; p<0.001), more symptomatic (New York Heart Association (NYHA) class: women 2.3+/-0.7 vs men 2.0+/-0.65; p<0.001), and presented with smaller valve areas (women 0.6+/-0.2 cm(2) vs men 0.7+/-0.2 cm(2); p<0.001) and higher mean pressure gradients (women 67.3+/-19.2 mm Hg vs men 62.2+/-20.0 mm Hg, p=0.001). Despite older age and more advanced disease in women, operative mortality did not differ. Survival after AVR by Kaplan-Meier analysis tended to be even better in women (92.8%, 89.8%, 81.4% vs men 89.1%, 86.6%, 76.3% at 1, 2 and 5 years, p=0.31). After division into age quintiles, the outcome of women was significantly better in patients older than 79 years (p=0.005). After adjustment for clinical characteristics, gender did not predict operative mortality and late outcome. Despite physical improvement in both groups after surgery, women remained more symptomatic (NYHA class: women 1.6+/-0.7 vs men 1.3+/-0.4; p=0.001). CONCLUSION: Although women referred to AVR are older and more symptomatic, operative and long-term mortality are not increased. In the oldest age group of 79 years and older, women even have a better outcome, presumably due to a longer mean life expectancy.

Role of amiodarone on the systemic inflammatory response induced by cardiac surgery: proinflammatory actions.

PURPOSE: Amiodarone (AMIO), a widely used anti-arrhythmic drug, has been shown to reduce the incidence of atrial fibrillation after cardiac surgery and also to exert immunomodulatory actions in vitro and proinflammatory effects in vivo. The present study investigated the immunomodulatory properties of AMIO in the inflammatory response induced by cardiac surgery with cardiopulmonary bypass (CPB). METHODS: In this double-blind, placebo-controlled trial, 20 patients undergoing elective coronary artery bypass graft were randomized to receive placebo or AMIO 600 mg day(-1) orally for seven days before surgery and 45 mg hr(-1) intravenously for 48 hr postoperatively. Plasma levels of the proinflammatory markers C-reactive protein (CRP), fibrinogen (FBG), tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and the antiinflammatory marker IL-10, were compared before and after surgery. RESULTS: Ninety-six hours after start of surgery, plasma levels of FBG had more than doubled (2.2 +/- 0.5-fold increase, P < 0.0001). Overall, FBG formation was significantly increased in the AMIO group (P = 0.048). Monocyte chemoattractant protein 1 secretion transiently increased four hours after start of surgery (6.6 +/- 4.5-fold increase) but rapidly declined thereafter, (P < 0.0001). There was a trend toward higher MCP-1 plasma concentrations in the AMIO group (P = 0.13). The plasma levels of CRP, TNF-alpha, IL-6 and Il-10 changed significantly over time, but were not altered by AMIO treatment. CONCLUSION: In the inflammatory response induced by cardiac surgery with CPB, our data suggest that AMIO treatment is associated with a selective trend toward proinflammatory actions.

Recent trends in heart transplantation: the University of Vienna experience.

Since the beginning of the University of Vienna Cardiac Transplant Program in 1984, 1086 heart transplant procedures have been performed through the end of 2007. One- and five-year survival has increased steadily over time (82% and 76%). Ten-year survival is 65%. Over the past 10 years our program has seen dramatic changes in patient selection, accepting now patients with more risk factors (Age, diabetes, elevated pulmonary resistance,..). Developments in immunosuppression have decreased incidence of infection, rejection and graft arteriosclerosis continuously. Our program continues to pursue novel strategies to improve the survival and quality of life of our heart transplant patients.

Vacuum assisted closure therapy for the treatment of sternal wound infections in neonates and small infants.

Sternal wound infections occur with an incidence between 0.4 and 5% in the adult as well as the pediatric population. However, in contrast to the adults, established treatment options do not exist in the pediatric population. We evaluated our preliminary results with 3 neonates, respectively, small infants (mean age 20.3+/-6 days) who underwent vacuum assisted closure (VAC) therapy for the treatment of sternal wound infections with the intention to enable secondary closure and preservation of the sternal bone. The mean VAC duration was 11.3 days, ranging from 10 to 12 days. After three dressing changes (every 48 to 72 h) the infection resolved and a secondary closure was feasible in all three patients. Isolated specimens were Candida albicans, Staphylococcus aureus and MRSA, respectively. These preliminary results show that VAC therapy is a promising alternative to the current treatment options available to neonates. Especially, the preservation of the sternal bone which enables normal thoracic cage stability and growth, is a clear advantage over the currently used muscle flaps.

Vascular dysfunction after coarctation repair is related to the age at surgery.

BACKGROUND: Despite repair of aortic coarctation, hypertension is frequent in adults and premature coronary and cerebrovascular disease remain of concern. Persistent impairment of arterial dilation has been suspected to contribute to abnormal blood pressure regulation. We tested the hypothesis that arterial reactivity is more likely to be impaired in patients corrected at older age. METHODS: We studied changes in brachial artery diameter in response to reactive hyperemia (FMD) and to nitroglycerin (NMD) in 36 patients and 25 controls. Depending on their age at surgery, patients were divided in group A (surgery <9 years) and group B (surgery > or =9 years). RESULTS: Cholesterol levels and percentage of smokers were similar in patients and controls, but 16 patients had arterial hypertension compared to none of the controls. Endothelium-dependent vasodilation, FMD, and endothelium-independent vasodilation, NMD, were significantly impaired in patients vs. controls (8.2+/-6.2% vs. 13.0+/-5.1%, p<0.001 and 12.9+/-8.0% vs. 18.8+/-9.2%, p<0.01, respectively), both, in hypertensives (8.3+/-6.0%, p<0.01 and 11.8+/-6.0%, p<0.05) and in normotensives (8.1+/-6.5% p<0.01 and 13.8+/-9.3%, p<0.05). However, FMD and NMD in patients of group A did not significantly differ from that in controls (10.0+/-6.7% n.s. and 15.0+/-7.6% n.s.), whereas they were lowest in patients of group B (5.5+/-4.3%, p<0.0001 and 9.6+/-7.7% p<0.001). CONCLUSIONS: Persistent impairment of FMD and NMD after repair of coarctation is more likely to be present in patients corrected at older age. It may be an important contributor to abnormal blood pressure regulation and late morbidity and mortality.

The oxygen dissociation curve: quantifying the shift.

An oxyhaemoglobin dissociation curve (ODC) quantifies the most important function of red blood cells and that is the affinity for oxygen and its delivery to the tissues. Oxygen affinity for haemoglobin plays a critical role in the delivery of oxygen to the tissues and is changed by shifting to the left or right. A shift to the left implies an increased oxygen affinity and, hence, tighter binding due to the higher oxygen saturation in relation to the pO2. On the other hand, a shift to the right corresponds to a decreased oxygen affinity and easier release of oxygen to the tissues. It is well known that the ODC shifts in response to changes in pH, pCO2 and 2,3 diphosphoglycerate. However, how much the ODC shifts has never been quantified. Arterial and venous blood gases were taken during cardiopulmonary bypass and two indices were used to quantify the shift of the ODC; the p50 shift and the SO2 difference. Arterial blood shifted to the right by 4 +/- 0.1 mmHg at a pH of 7.24 and shifted to the left by -3.5 +/- 0.05 mmHg at a pH of 7.51. The change in arterial saturation was minimal, rising by 0.8% and dropping by -5% and did not correlate to p50 shifting and changes in pH, but demonstrated changes dependent on the concentration of dyshaemoglobins. The venous blood exhibited a greater range of p50 shifting at each pH value. At a pH of 7.24, the p50 shifted to the right by 4.8 +/- 2 mmHg and at a pH of 7.51 the p50 shifted to the left by -4 +/- 1.8 mmHg. Unlike the arterial blood, the change in saturation correlated well to p50 shifting. It is shown here for the first time how much the curve shifts with changes in pH and how this may be used to evaluate treatment strategies.

Early postoperative prediction of cerebral damage after pediatric cardiac surgery.

BACKGROUND: Cerebral damage is a serious complication of pediatric cardiac surgery. Early prediction of actual risk can be useful in counseling of parents, and in early diagnosis and rehabilitation therapy. Also, if all children at risk could be identified therapeutic strategies to limit perioperative cerebral damage might be developed. The aim of this study is to create a mathematical model to predict risk of neurologic sequelae within 24 hours after surgery using simple and readily available clinical measurements. METHODS: The hospital records of 534 children after cardiac surgery were reviewed. Variables examined were age at operation, diagnosis, use of cardiopulmonary bypass, arterial and central venous oxygen saturation, serum glucose, lactate and creatine kinase, mean arterial pressure, and body temperature. The endpoint for each study patient was the occurrence or lack of occurrence of seizures, movement or developmental disorders, cerebral hemorrhage, infarction, hydrocephalus, or marked cerebral atrophy. Univariate and multivariate regression analyses were used to evaluate the predictive power of the investigated factors as well as to create a predictive model. RESULTS: In 6.26% of children symptoms of cerebral damage were found. Significant risk factors were age at surgery, more complex malformations, metabolic acidosis, and increased lactate (odds ratio: age, 0.882/yr [0.772-1.008]; complex malformations, 10.32 [1.32-80.28]; arterial pH more than 7.35 to 0.4 [0.18-0.89]; lactate -1.018 per mg/dL [1.006-1.03]). CONCLUSIONS: It is possible to quantify the risk of appearance of symptoms of cerebral damage after cardiac surgery within 24 hours using simple and readily available clinical measurements.

Methemoglobin formation in children with congenital heart disease treated with inhaled nitric oxide after cardiac surgery.

OBJECTIVE: Inhaled nitric oxide (NO) is used as a therapy of pulmonary hypertension in children after cardiac surgery. Hemoglobin binds to NO with great affinity and forms methemoglobin by oxidation in the erythrocyte. Once produced, methemoglobin is unable to transport and unload oxygen in the tissues. The amount of available hemoglobin in the body for oxygen transport is thereby reduced. Anemia, acidosis, respiratory compromise and cardiac disease may render patients more susceptible than expected for a given methemoglobin level. The goal of the present study was to review the cumulative effect of inhaled NO on methemoglobin formation in critically ill children. We therefore looked for methemoglobin levels in children with congenital heart disease after cardiac surgery who were treated with inhaled NO in a range of 5-40 ppm. METHODS: We retrospectively reviewed the medical charts of 38 children with congenital heart disease after cardiac surgery. We extracted demographic data and physiological measurements at the following time points: (1) T0 = before starting inhaled NO therapy, (2) T1 = 24 h after the beginning of inhaled NO therapy, (3) T2 = half-time therapy, (4) T3 = end of therapy, (5) T4 = 24 h after finishing inhaled NO therapy. RESULTS: The median duration of inhaled NO therapy was 5.5 days (interquartile range 6, range 2-29), NO concentrations at T1 and T2 were 16 ppm (10, 5-40) and 12.5 ppm (12.3, 2-40), respectively. The median cumulative dose of inhaled NO was 1699 ppm (2313, 193-7018). Methemoglobin levels increased moderately, but significantly, during therapy ( T0 vs T1 p<0.05 and T0 vs T2 p<0.001). The highest methemoglobin level measured was 3.9%. Methemoglobin levels correlated positively with the inhaled NO doses applied at T1 ( r(2)=0.8376; p<0.01) and at T2 ( r(2)=0.8945; p<0.01). At T1 the methemoglobin level correlated negatively with the T1 blood pH value. The overall mortality rate was 13.2% (5 of 38 study patients died). There was no significant difference in methemoglobin levels between survivors and non-survivors. CONCLUSION: We conclude from our data that the use of inhaled NO therapy for children with congenital heart disease after cardiac surgery in the described range of 5-40 ppm, resulting in a maximum of 4% methemoglobin blood level, is feasible and safe. However, we recommend the use of the minimal effective dose of inhaled NO and continuous monitoring of methemoglobin levels, especially in cases of anemia or sepsis in critically ill children.

Cold water submersion and cardiac arrest in treatment of severe hypothermia with cardiopulmonary bypass.

In the paediatric population, submersion injury with drowning or near-drowning represents a significant cause of morbidity and mortality. This study reviews retrospectively our own experiences and the literature on the use of cardiopulmonary bypass (CPB) to rewarm paediatric victims of cold water submersion who suffer severe hypothermia (<28 degrees C) and cardiac arrest (asystole or ventricular fibrillation). In addition to three children treated at our institution, nine other victims were found in the literature. In this cohort of 12 children aged between 2 and 12 years, there was a tendency to better outcome with lower core temperature at the beginning of extracorporeal circulation (mean temperature in nine survivors, 20 degrees C; in three non-survivors, 25.5 degrees C). The lowest temperature survived was 16 degrees C. Neither base excess, pH nor serum potassium levels were reliable prognostic factors. The lowest base excess in a survivor was -36.5 mmol/l, the lowest pH 6.29. We consider CPB as the method of choice for resuscitation and rewarming of children with severe accidental hypothermia and cardiac arrest (asystole or ventricular fibrillation). Compared with adults, children, especially smaller ones, require special consideration with regard to intravenous cannulation as drainage can be inadequate using femoral-femoral cannulation. In hypothermic children we advocate, therefore, emergency median sternotomy. Until more information regarding prognostic factors are available, children who are severely hypothermic and clinically dead after submersion in cold water--even if for an unknown length of time--should receive cardiopulmonary resuscitation (CPR) and be transported without delay to a facility with capabilities for CPB instituted via a median sternotomy.

The University of Vienna experience in heart transplantation.

Since the University of Vienna Cardiac Transplant Program began in 1984, 892 heart transplant procedures have been performed through the end of 2001. One- and five-year survival has increased steadily over time to 80% and 75%, respectively, in the most recent cohort. Ten-year survival is 55%. Over the past 10 years our program has seen dramatic changes in patient selection, accepting now patients with more risk factors (age, diabetes, elevated pulmonary resistance,..). Developments in immunosuppression have decreased the incidence of infection, rejection and graft arteriosclerosis continuously. Our program continues to pursue novel strategies to improve the survival and quality of life of our heart transplant patients.